Neutrinos shot through 780 feet of stone, spell out their name

Researchers used a particle accelerator and detector to send a message without …

A group of researchers communicated a message through 780 feet of solid stone using a beam of neutrinos, the University of Rochester announced Wednesday. When the message came out the other side, the scientists were able to read it perfectly: it said, perhaps unimaginatively, "Neutrino."

Neutrinos are nearly massless and travel very close to the speed of light. Because they only interact with matter via gravity and the weak force, they can pass through substances, including entire planets, with little disruption. Scientists have talked about using the particles as a messaging alternative to cables or satellites, sending messages to the other side of the earth by going through the earth, rather than going around the long way or sending messages into space and back again.

The equipment to send neutrino messages is still wildly expensive. The researchers who sent the "Neutrino" message used a particle accelerator at Fermilab with a 2.5-mile-circumference track and the 5-ton particle detector named MINERvA. To signal the message, the scientists used binary code, with a group of neutrinos fired corresponding to a 1 and no neutrinos fired corresponding to a 0. Even MINERvA can only detect about one in 10 billion neutrinos, so the particles had to be fired in very large numbers to register.

Because the equipment is so expensive, actual communication with neutrinos is still a long way off. Still, the authors note that the particles are barely affected by gravity and not affected at all by magnetism; eventually, they could provide a stable alternative to the electromagnetic waves we use now.

When I read the recent article about neutrinos seeming to travel faster than light after travelling through hundreds of miles of earth, I thought to myself "Wouldn't it be interesting to try and send messages via neutrino beams?". Turns out I'm not the only one!

Give it 30 years and every house will have a transmitter and detector.

There are a few problems to overcome. For example, it's ok to send a billion neutrinos and pick up only one. Unless the neighbors are also trying to get a message and another 1-in-a-billion neutrino hits their detector too. These messages go through everything, that is bad for filtering one message out from another.

Hmm, thru earth light speed. I wonder what the latency would be on playing a asian MMO that way.

Some quick napkin math says ~(12700km / 300 000km/s) * 1000ms/s = 42.3 ms. That is just a straight light through the diameter of the earth though. Maybe something like 100ms would be practical? Heck I ping 100ms to a server in a neighboring state, getting 100ms to the other side of the world would be pretty wicked.

This could shave a few milliseconds off the trip from London to Tokyo (1/4 of the way around the earth) by travelling straight line. Actually, fiber is slower than the speed of light, so this could as much as cut it in half. Could be a serious advantage in financial arbitrage.

Hmm, thru earth light speed. I wonder what the latency would be on playing a asian MMO that way.

Some quick napkin math says ~(12700km / 300 000km/s) * 1000ms/s = 42.3 ms. That is just a straight light through the diameter of the earth though. Maybe something like 100ms would be practical? Heck I ping 100ms to a server in a neighboring state, getting 100ms to the other side of the world would be pretty wicked.

maybe a stupid remark, but targetting the receptor from the other side of the earth (or even from NY to Tokyo) maybe will be the toughest part ?It's easy to calculate how a tiny angle error can miss the receptor (which I won't do).

This is pretty cool and I'm highly interested in what sort of applications this may have. If neutrinos pass through substances (all the time) with no affect, how did the message get "written?"

*just curious*

*edited to explain: Before anyone asks, I did read the article and did read that a particle detector was used, but I was curious how it was able to be "written."

The applications are limited at the moment. Initial interest in this came from the US Navy to see if this could be used to communicate with submarines (the answer is it is not practical). Other potential uses are communicating across the solar system, across interstellar space, or with the darkside of the moon if we ever develop a presence there. So, nothing too useful yet.

As to the how, neutrinos are created by first creating unstable particles (pions and kaons) that emit neutrinos amongst other particles as they decay back to stable particles. Neutrinos are *slightly* affected by traveling through the Earth, but not enough to be attenuated in any appreciable way (the mean free path of a neutrino in *lead* is more than a lightyear). The experiment expected a pulse every ~2.2 seconds. If the beam was on, that corresponds to a 1. In that case, the experiment should observe neutrinos interacting to create muons (a heavy cousin to the electron) about 80% of the time within the detector. For this reason, the message had to be repeated several times. If it was off, that corresponds to a 0 and no muons should be observed. These bits were then used to encode the message in a form of ascii.

Still, the authors note that the particles are barely affected by gravity and not affected at all by magnetism;

Barely affected by gravity; yes, they only feel 9.8m/s/s of acceleration in the earth's magnetic field! As opposed to light, which only falls at 9.8 m/s/s in the earth's magnetic field, and cannonballs which fall at a massive 9.8m/s/s off of the leaning tower of pisa.

Just because whoever wrote the press release linked mass to being affected by gravity, doesn't mean that Ars has to parrot the same mistake.

Spaham wrote:

maybe a stupid remark, but targetting the receptor from the other side of the earth (or even from NY to Tokyo) maybe will be the toughest part ?It's easy to calculate how a tiny angle error can miss the receptor (which I won't do).

This is only an issue if you can make a really, really tight beam, which we can't do (at least at the moment). IIRC the NuMI beam at fermilab is kilometers across only 700km away.

Also, this really isn't that hard to do at a range of 300m. The intensities required (or the sheer mass of the detector) is completely prohibitive at any ranges to be of any use whatsoever.

"Neutrinos are nearly massless and travel very close to the speed of light, so they can pass through substances, including entire planets, with little disruption"

This is strictly not true. Neutrinos sail right through stuff because they only interact weakly and do not interact with light. Electrons have a very small mass compared to atoms and protons and yet one can not say that they barely interact because of their small mass.

"Neutrinos are nearly massless and travel very close to the speed of light, so they can pass through substances, including entire planets, with little disruption"

This is strictly not true. Neutrinos sail right through stuff because they only interact weakly and do not interact with light. Electrons have a very small mass compared to atoms and protons and yet one can not say that they barely interact because of their small mass.

I was just about to say roughly the same thing.

Also, I very much doubt that we'll ever use neutrinos for every-day communication. The fact that they can pass through entire planets without hitting anything means that they are by nature very difficult to detect... So unless there is something really important that we don't yet know about neutrinos, then I don't think it's ever going to be easy to send or receive these kinds of neutrino signals. It will always require an enormous detector and a powerful emitter.

Also, I very much doubt that we'll ever use neutrinos for every-day communication. The fact that they can pass through entire planets without hitting anything means that they are by nature very difficult to detect... So unless there is something really important that we don't yet know about neutrinos, then I don't think it's ever going to be easy to send or receive these kinds of neutrino signals. It will always require an enormous detector and a powerful emitter.

I disagree. Just because it is not practical now doesn't mean it won't be in the future. You can fill a dump truck with all the advantages, and they are so attractive that I predict it will be implausible for neutrino.net to not come into play - some day.

In the MINERvA detector, how can it distinguished the neutrinos sent by the researchers and other "extra terrestrial" neutrinos which were crossing the Earth at the same time?

A fluctuation of 5 sigma above background coming from a particular direction would be sufficient. They may also have used high energy neutrinos and a detector that responds only above a certain suitably high threshold to remove background. Solar neutrinos, the dominant background, are relatively low energy.